I. Field of the Invention
The present invention concerns improvements in or relating to vehicles, especially but not exclusively electrically propelled vehicles, and particularly to power assisted steering for wheeled electrically propelled vehicles.
II. Description of the Prior Art
Many electrically propelled vehicles, for example fork-lift trucks, incorporate a hydraulic power steering system which is supplied by pressurized hydraulic fluid from an electrically driven pump. As the power supply from the pump is taken from the vehicle's battery it is desirable that it is only actuated when there is a demand for powered steering assistance. One method of achieving this object has been to incorporate a microswitch in the power supply to the pump which causes power to the pump to be cut off when the vehicle's accelerator pedal is not depressed. This prior proposal, however, has the disadvantage that no power steering assistance is given if the vehicle is moving and the accelerator is not depressed, for example when it is coasting downhill or coasting to a stop.